The isolation of biological materials such as nucleic acids or proteins from complex biological mixtures such as e.g. clinical samples has been of considerable significance especially for diagnostic purposes.
Examples for diagnostic applications of nucleic acid sample preparation comprise preparation and subsequent detection of viruses such as Human Papilloma Virus (HPV), West Nile Virus (WNV) or the routine screening of blood donations for the presence of Human Immunodeficiency Virus (HIV), Hepatitis-B (HBV) and/or C Virus (HCV). Furthermore, said amplification techniques are suitable for bacterial targets such as mycobacteria or Chlamydia trachomatis and Neisseria gonorrhoeae, or the analysis of oncology markers.
Numerous different methods have been developed in the art, e.g. denaturing, precipitating and removing undesired components in a sample with subsequent precipitation and isolation of the analyte in question (for example alcohol-based precipitation of nucleic acids). Another approach is the binding of the respective biological material to a solid support material which may be provided, e.g., in the form of chromatographic columns. For diagnostic purposes, and especially for the automated isolation of biological materials subject to subsequent medium- or high-throughput analysis, binding particles are often used. Such particles can have functionalized surfaces, i.e. they are often coated with antibodies, nucleic acid capture probes or the like, in order to bind the desired analyte. Alternatively, they may have unmodified surfaces such as glass surfaces particularly for the isolation of nucleic acids.
However, target nucleic acids to be analyzed for diagnostic purposes can be present in a variety of different sources. In practice, the sample preparation procedure for nucleic acids in different sources is usually adapted to                1. the type of fluid sample        2. the type of nucleic acid.        
Other criteria may also have to be taken into account when isolating different nucleic acids from different sources. The prior art has addressed this diversity by providing different methods of preparation for said different types of samples.
An improved method for isolating at least a first and a second target nucleic acid from a plurality of different types of fluid samples is provided by the present invention.